| /////////////////////////////////////////////////////////////////////////////// |
| // repeat_end_matcher.hpp |
| // |
| // Copyright 2008 Eric Niebler. Distributed under the Boost |
| // Software License, Version 1.0. (See accompanying file |
| // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_REPEAT_END_MATCHER_HPP_EAN_10_04_2005 |
| #define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_REPEAT_END_MATCHER_HPP_EAN_10_04_2005 |
| |
| // MS compatible compilers support #pragma once |
| #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| # pragma once |
| #endif |
| |
| #include <boost/mpl/bool.hpp> |
| #include <boost/xpressive/detail/detail_fwd.hpp> |
| #include <boost/xpressive/detail/core/quant_style.hpp> |
| #include <boost/xpressive/detail/core/state.hpp> |
| |
| namespace boost { namespace xpressive { namespace detail |
| { |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // repeat_end_matcher |
| // |
| template<typename Greedy> |
| struct repeat_end_matcher |
| : quant_style<quant_none, 0, false> |
| { |
| typedef Greedy greedy_type; |
| int mark_number_; |
| unsigned int min_, max_; |
| mutable void const *back_; |
| |
| repeat_end_matcher(int mark_nbr, unsigned int min, unsigned int max) |
| : mark_number_(mark_nbr) |
| , min_(min) |
| , max_(max) |
| , back_(0) |
| { |
| } |
| |
| template<typename BidiIter, typename Next> |
| bool match(match_state<BidiIter> &state, Next const &next) const |
| { |
| // prevent repeated zero-width sub-matches from causing infinite recursion |
| sub_match_impl<BidiIter> &br = state.sub_match(this->mark_number_); |
| |
| if(br.zero_width_ && br.begin_ == state.cur_) |
| { |
| return next.skip_match(state); |
| } |
| |
| bool old_zero_width = br.zero_width_; |
| br.zero_width_ = (br.begin_ == state.cur_); |
| |
| if(this->match_(state, next, greedy_type())) |
| { |
| return true; |
| } |
| |
| br.zero_width_ = old_zero_width; |
| return false; |
| } |
| |
| // greedy, variable-width quantifier |
| template<typename BidiIter, typename Next> |
| bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const |
| { |
| sub_match_impl<BidiIter> &br = state.sub_match(this->mark_number_); |
| |
| if(this->max_ > br.repeat_count_) |
| { |
| ++br.repeat_count_; |
| // loop back to the expression "pushed" in repeat_begin_matcher::match |
| if(next.top_match(state, this->back_)) |
| { |
| return true; |
| } |
| else if(--br.repeat_count_ < this->min_) |
| { |
| return false; |
| } |
| } |
| |
| // looping finished, continue matching the rest of the pattern |
| return next.skip_match(state); |
| } |
| |
| // non-greedy, variable-width quantifier |
| template<typename BidiIter, typename Next> |
| bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const |
| { |
| sub_match_impl<BidiIter> &br = state.sub_match(this->mark_number_); |
| |
| if(this->min_ <= br.repeat_count_) |
| { |
| if(next.skip_match(state)) |
| { |
| return true; |
| } |
| } |
| |
| if(this->max_ > br.repeat_count_) |
| { |
| ++br.repeat_count_; |
| if(next.top_match(state, this->back_)) |
| { |
| return true; |
| } |
| --br.repeat_count_; |
| } |
| |
| return false; |
| } |
| }; |
| |
| }}} |
| |
| #endif |